Ankle locks from the guard

Can any bjj players give me some tips on getting ankle locks on from my opponents guard? Also, what other positions are good to start an ankle lock from? I have no problem pulling them on fellow noobs but I can't seem to hold onto them or get my legs in the right position against anyone better.

I think footlocks work well with a good guard pass- if you're obviously looking for footlocks everytime you break his guard open, I think the chances are slimmer than if you were insisting on passing and then switched to the foot when it presented itself. Im personally not a big fan of footlocks, so you wont see me do them very often.

As far as other positions are concerned, there are alot of setups for footlocks and knee locks from the butterfly guard, if you can get your hips under your opponent.

I haven't learned any submissions involving the legs yet.
Are they even taught to white belts or are they normally saved for more advanced students?

Generally, BJJ rules are no leg locks at white belt, some straight ones like achilles at blue, kneebars at purple, and maybe some twisting stuff like heelhooks at brown or higher. No-gi competitions are usually more liberal with them and allow all sorts of locks that are not allowed in gi competition.